If you know the 4 digit extension, then street address is unnecessary because post office sorts by zip code first, 4 digit extension is the building (house, apartment, etc)
4 digit extension also accelerates delivery time by at least 24 hours, usually 48 hours, sometimes 3 days
Zip codes are sequential moving east to right
06520 = New Haven CT
90210 = Beverly Hills
If you know the 4 digit extension, then street address is unnecessary because post office sorts by zip code first, 4 digit extension is the building (house, apartment, etc)
4 digit extension also accelerates delivery time by at least 24 hours, usually 48 hours, sometimes 3 days
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